Measles Outbreaks Across the US Spread As Vaccination Rates Fall

A dose of measles, mumps and rubella virus vaccine is prepared at the Salt Lake County Health Department in Salt Lake City.

Photographer: George Frey/Getty Images

Measles outbreaks have spread across the US to reach 41 states. The largest ongoing cluster in Utah and Arizona has now grown into the second-biggest outbreak of the year.

Utah reported a total of 58 infections Thursday, bringing the tally for Utah and Arizona to 142 so far this year. The Arizona Department of Health has reported 84 cases and three hospitalizations. A total of 1,618 infections have been reported nationwide by the US Centers for Disease Control and Prevention this year, the largest outbreak in three decades.